From: Praveen Kumar <kumarpraveen@xxxxxxxxxxxxxxxxxxx> Sent: Tuesday, November 22, 2022 4:01 AM
>
> On 11/22/2022 5:47 AM, Nir Levy wrote:
> > The reference must be released when device_register(&child_device_obj->device)
> failed.
> > Fix this by adding 'put_device()' in the error handling path.
> > ---
> > drivers/hv/vmbus_drv.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> > index 8b2e413bf19c..e592c481f7ae 100644
> > --- a/drivers/hv/vmbus_drv.c
> > +++ b/drivers/hv/vmbus_drv.c
> > @@ -2082,6 +2082,7 @@ int vmbus_device_register(struct hv_device
> *child_device_obj)
> > ret = device_register(&child_device_obj->device);
> > if (ret) {
> > pr_err("Unable to register child device\n");
> > + put_device(&child_device_obj->device);
>
> I think this patch is not required, as device_add (device_register->device_add) will
> put_device for any failure within.
> Please do share the specific flow which you think might need this fix. Thanks.
>
The put_device() done in the exit paths for device_add() pairs with the
get_device() done at the very beginning of device_add(). The put_device()
proposed by this patch *is* needed to properly clean up.
But someone else (Yang Yingliang <yangyingliang@xxxxxxxxxx>) has already
submitted a patch to add the put_device(). It's currently in the hyperv-fixes
tree waiting to merge with Linus' tree. See https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/commit/?h=hyperv-fixes&id=25c94b051592c010abe92c85b0485f1faedc83f3.
Michael
